TGFB1 and metastatic neoplasm: CYLD is a tumour suppressor gene involved in regulation of several proliferation-associated pathways, including NF-κB, Wnt, Notch and TGF-β, potentially suggesting that metastatic tumour heterogeneity driven by further adaptation to increased proliferative phenotypes does occur, though less ubiquitous than the heterogeneity observed in primary tumours.